With a month to go before Wisconsin’s gubernatorial recall vote, Democrats’ case against Scott Walker is less about collective bargaining policy itself than the notion that the governor masked his intentions to limit it as part of the sweeping budget bill he championed last spring. The argument, which Politifact endorsed, is that Walker obscured his plan to attack public-employee unions during his run for office. Walker has repeatedly denied this. But in a new video released to the Milwaukee Journal Sentinel by a documentary filmmaker, Wisconsin Democratic Party officials say there’s now hard evidence that the governor has a history of obfuscation.

The video shows Scott Walker using the term “divide and conquer” to describe his plan for curbing collective bargaining to donor Diane Hendricks in January, 2011. The partial transcript of Walker’s conversation with Hendricks, who has donated more than $500,000 to help him survice the recall campaign, is more interesting than the 28-second video snippet. It reveals the political calculation Walker made, which was that the best way to go after public-employee unions was to tie collective bargain to the budget bill and argue the only alternative is to raise taxes. “The key is by tying it to the budget, there’s no way to unravel that. Because unless they’re going to come up with $800 million for example – it’s not exactly that amount, but it’s close – there’s no way they cannot pass that unless they’re going to pass a tax increase,” Walker says.

The “divide and conquer” phrase dovetails nicely with the Barrett campaign’s core message, which is that their candidate would unify a state torn asunder by an ideological warrior less interested in the middle class than becoming a national conservative hero. And Walker did divide his potential opposition by exempting cops and firefighters from his plan, thereby avoiding a fate such as the one that befell John Kasich in Ohio. This isn’t the first time Walker has been captured outlining his rationale; last year he was taped having a phone conversation with a blogger posing as David Koch. Still, this is a useful cudgel for Barrett and the Wisconsin Democrats.

The Walker campaign, meanwhile, has been eager to look to the future, which is a sensible tactic in an election triggered by outrage at the governor’s tenure. Yesterday it held a press call to highlight a letter conservative legislators sent to Barrett, urging him to release concrete details about how he intends to tackle the state’s budget. Barrett, by contrast, wants the make the race a referendum on the governor. This too is logical: Barrett, who’s hardly been an ally of unions, may be better off running as a cipher than on his own record, at least as it pertains to the people who started the recall process in the first place.